Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

A method for sorting among a plurality of potential route plans for
operating an autonomous ground based machine includes a step of creating
a virtual model of a terrain of a work site. A first virtual lane having
at least one measurable lane constraint is created within the virtual
model. A first virtual machine footprint is created and has a first
virtual movement profile corresponding to an actual autonomous movement
profile of the autonomous machine. The first virtual machine footprint is
moved from a starting position along the first virtual lane to an ending
position according to the first virtual movement profile. During the
moving step, the first virtual machine footprint is compared to the at
least one measurable lane constraint. The first proposed route plan is
then designated as either viable or unacceptable based on the comparison.

Claims:

1. A method for sorting among a plurality of potential route plans for
operating an autonomous ground based machine at a work site, the method
comprising: creating a virtual model of a terrain of the work site;
creating a first virtual lane within the virtual model, wherein the first
virtual lane corresponds to a first proposed route plan of the plurality
of potential route plans and has at least one measurable lane constraint;
creating a first virtual machine footprint having a first virtual
movement profile, wherein the first virtual machine footprint corresponds
to an actual footprint of the autonomous ground based machine and the
first virtual movement profile corresponds to an actual autonomous
movement profile of the autonomous ground based machine; moving the first
virtual machine footprint from a starting position along the first
virtual lane to an ending position along the first virtual lane according
to the first virtual movement profile; during the moving step, comparing
the first virtual machine footprint to the at least one measurable lane
constraint; and designating the first proposed route plan as either
viable or unacceptable based on the comparison of the first virtual
machine footprint to the at least one measurable lane constraint.

2. The method of claim 1, wherein the moving step includes moving the
first virtual machine footprint according to a predetermined acceleration
rate, a predetermined deceleration rate, and a predetermined turning
radius.

3. The method of claim 1, wherein the comparing step includes comparing
the first virtual machine footprint to at least one of a width of the
first virtual lane, a grade of the first virtual lane, and a curvature of
the first virtual lane.

4. The method of claim 1, further including: creating a second virtual
machine footprint having a second virtual movement profile that is
different than the first virtual movement profile; moving the second
virtual machine footprint along the first virtual lane according to the
second virtual movement profile; comparing the second virtual machine
footprint to the at least one measurable lane constraint while the second
virtual machine footprint moves along the first virtual lane; and
designating the first proposed route plan as either viable or
unacceptable based on the comparison of both of the first virtual machine
footprint and the second virtual machine footprint to the at least one
measurable lane constraint.

5. The method of claim 4, further including: modifying movement of one of
the first virtual machine footprint and the second virtual machine
footprint based on a current virtual position of another of the first
virtual machine footprint and the second virtual machine footprint.

6. The method of claim 4, further including: moving the first virtual
machine footprint and the second virtual machine footprint according to a
predetermined work cycle, wherein the predetermined work cycle
corresponds to the first proposed route plan; measuring at least one of a
cycle time and a wait time corresponding to movement of the first virtual
machine footprint and the second virtual machine footprint according to
the predetermined work cycle a predetermined number of times; comparing
the at least one of the cycle time and the wait time to an acceptable
time value; and designating the first proposed route plan as either
viable or unacceptable based on the comparison of the at least one of the
cycle time and the wait time to the acceptable time value.

7. The method of claim 4, further including: creating a second virtual
lane within the virtual model, wherein the second virtual lane
corresponds to the first proposed route plan and has at least one
measurable lane constraint, wherein the first virtual lane and the second
virtual lane intersect; and moving a plurality of virtual machine
footprints along both of the first virtual lane and the second virtual
lane.

8. The method of claim 7, further including: moving the plurality of
virtual machine footprints according to a predetermined work cycle,
wherein the predetermined work cycle corresponds to the first proposed
route plan; measuring at least one of a cycle time and a wait time
corresponding to movement of the virtual machine footprints according to
the predetermined work cycle a predetermined number of times; comparing
the at least one of the cycle time and the wait time to an acceptable
time value; and designating the first proposed route plan as either
viable or unacceptable based on the comparison of the at least one of the
cycle time and the wait time to the acceptable time value.

9. A virtual environment for sorting among a plurality of potential route
plans for operating an autonomous ground based machine at a work site,
comprising: a virtual model of a terrain of the work site; a first
virtual lane within the virtual model, wherein the first virtual lane
corresponds to a first proposed route plan of the plurality of potential
route plans and has at least one measurable lane constraint; a first
virtual machine footprint having a first virtual movement profile,
wherein the first virtual machine footprint corresponds to an actual
footprint of the autonomous ground based machine and the first virtual
movement profile corresponds to an actual autonomous movement profile of
the autonomous ground based machine; an electronic processor configured
to move the first virtual machine footprint from a starting position
along the first virtual lane to an ending position along the first
virtual lane according to the first virtual movement profile, compare the
first virtual machine footprint to the at least one measurable lane
constraint while the first virtual machine footprint is moving, and
designate the first proposed route plan as either viable or unacceptable
based on the comparison of the first virtual machine footprint to the at
least one measurable lane constraint.

10. The virtual environment of claim 9, wherein the first virtual
movement profile includes a predetermined acceleration rate, a
predetermined deceleration rate, and a predetermined turning radius.

11. The virtual environment of claim 9, wherein the at least one
measurable lane constraint includes at least one of a width of the first
virtual lane, a grade of the first virtual lane, and a curvature of the
first virtual lane.

12. The virtual environment of claim 9, wherein the electronic processor
is further configured to: create a second virtual machine footprint
having a second virtual movement profile that is different than the first
virtual movement profile; move the second virtual machine footprint along
the first virtual lane according to the second virtual movement profile;
compare the second virtual machine footprint to the at least one
measurable lane constraint while the second virtual machine footprint
moves along the first virtual lane; and designate the first proposed
route plan as either viable or unacceptable based on the comparison of
both of the first virtual machine footprint and the second virtual
machine footprint to the at least one measurable lane constraint.

13. The virtual environment of claim 12, wherein the electronic processor
is further configured to: modify movement of one of the first virtual
machine footprint and the second virtual machine footprint based on a
current virtual position of another of the first virtual machine
footprint and the second virtual machine footprint.

14. The virtual environment of claim 12, wherein the electronic processor
is further configured to: move the first virtual machine footprint and
the second virtual machine footprint according to a predetermined work
cycle, wherein the predetermined work cycle corresponds to the first
proposed route plan; measure at least one of a cycle time and a wait time
corresponding to movement of the first virtual machine footprint and the
second virtual machine footprint according to the predetermined work
cycle a predetermined number of times; compare the at least one of the
cycle time and the wait time to an acceptable time value; and designate
the first proposed route plan as either viable or unacceptable based on
the comparison of the at least one of the cycle time and the wait time to
the acceptable time value.

15. The virtual environment of claim 12, wherein the electronic processor
is further configured to: create a second virtual lane within the virtual
model, wherein the second virtual lane corresponds to the first proposed
route plan and has at least one measurable lane constraint, wherein the
first virtual lane and the second virtual lane intersect; and move a
plurality of virtual machine footprints along both of the first virtual
lane and the second virtual lane.

16. The virtual environment of claim 15, wherein the electronic processor
is further configured to: move the plurality of virtual machine
footprints according to a predetermined work cycle, wherein the
predetermined work cycle corresponds to the first proposed route plan;
measure at least one of a cycle time and a wait time corresponding to
movement of the virtual machine footprints according to the predetermined
work cycle a predetermined number of times; compare the at least one of
the cycle time and the wait time to an acceptable time value; and
designate the first proposed route plan as either viable or unacceptable
based on the comparison of the at least one of the cycle time and the
wait time to the acceptable time value.

Description:

TECHNICAL FIELD

[0001] The present disclosure relates generally to a virtual environment,
and more particularly to a virtual environment and method for evaluating
a proposed route plan for operating an autonomous machine at a work site.

BACKGROUND

[0002] Utilization of autonomous machines is becoming more prevalent and
offers particular advantages in the mining industry. Specifically,
autonomous machines may be operated in environments unsuitable for human
operators, such as, for example, at high altitudes or in sparsely
populated desert regions. In addition, autonomous machines may be
operated for longer periods of time than manned machines, thus providing
increased productivity, and may be operated according to strict control
strategies aimed at optimizing efficiency and reducing emissions.
Further, by optimizing operation, maintenance costs for the autonomous
machine may potentially be reduced.

[0003] Autonomous control is accomplished by providing the autonomous
machine with a machine control system that includes a positioning unit
and a navigation unit. The navigation unit uses machine position and
orientation information generated by the positioning unit to maneuver the
autonomous machine according to a route plan, which includes, for
example, designated lanes, travel paths, routes, hazards, and the like.
The route plan may be generated and updated at a central control system
and transmitted to the autonomous machine, as needed. Typically, the
route plan will be validated to ensure the autonomous machine may
successfully navigate the designated lanes. In particular, a manned,
autonomous, or semi-autonomous machine may be operated along a
constructed lane at the mine site to verify the suitability of the lane
for autonomous operation prior to the incorporation of the constructed
lane into the route plan. This real world validation may be both time
consuming and costly, particularly if the constructed lane is found to be
unsuitable and must be modified or moved.

[0004] U.S. Pat. No. 6,393,362 to Burns teaches an onboard strategy for
autonomous vehicle collision avoidance. In particular, the strategy of
Burns teaches the creation of a safety envelope corresponding to each of
the autonomous vehicles that is based on the vehicle's geometry, speed,
and guidance control errors and/or tolerances. Positions of the safety
envelopes are predicted as each of the autonomous vehicles travel along a
trajectory. If a potential overlap of safety envelopes of two or more
vehicles is identified, a control strategy for one of the autonomous
vehicles is modified to avoid the potential collision. This onboard
control strategy may prove useful in real-time vehicle avoidance, but
does not teach or suggest autonomous vehicle simulation for route
planning purposes.

[0005] The present disclosure is directed to one or more of the problems
or issues set forth above.

SUMMARY OF THE DISCLOSURE

[0006] In one aspect, a method for sorting among a plurality of potential
route plans for operating an autonomous ground based machine at a work
site includes a step of creating a virtual model of a terrain of the work
site. A first virtual lane, which corresponds to a first proposed route
plan of the plurality of potential route plans and has at least one
measurable lane constraint, is created within the virtual model. A first
virtual machine footprint, corresponding to an actual footprint of the
autonomous ground based machine, is created and has a first virtual
movement profile. The first virtual movement profile corresponds to an
actual autonomous movement profile of the autonomous ground based
machine. The first virtual machine footprint is moved from a starting
position along the first virtual lane to an ending position along the
first virtual lane according to the first virtual movement profile.
During the moving step, the first virtual machine footprint is compared
to the at least one measurable lane constraint. The first proposed route
plan is then designated as either viable or unacceptable based on the
comparison of the first virtual machine footprint to the at least one
measurable lane constraint.

[0007] In another aspect, a virtual environment for sorting among a
plurality of potential route plans for operating an autonomous ground
based machine at a work site includes a virtual model of a terrain of the
work site. The virtual model also includes a first virtual lane
corresponding to a first proposed route plan of the plurality of
potential route plans and having at least one measurable lane constraint.
A first virtual machine footprint corresponding to an actual footprint of
the autonomous ground based machine has a first virtual movement profile
corresponding to an actual autonomous movement profile of the autonomous
ground based machine. An electronic processor is configured to move the
first virtual machine footprint from a starting position along the first
virtual lane to an ending position along the first virtual lane according
to the first virtual movement profile. The electronic processor compares
the first virtual machine footprint to the at least one measurable lane
constraint while the first virtual machine footprint is moving, and
designates the first proposed route plan as either viable or unacceptable
based on the comparison of the first virtual machine footprint to the at
least one measurable lane constraint.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a schematic diagram of an exemplary system for operating
an autonomous machine at a work site, according to the present
disclosure;

[0009]FIG. 2 is a graphical representation of a virtual environment,
depicting a simulation of a first virtual machine footprint along a first
virtual lane corresponding to a first proposed route plan, according to
one aspect of the present disclosure;

[0010]FIG. 3 is another graphical representation of the virtual
environment, depicting a simulation of a second virtual machine footprint
along the first virtual lane, according to another aspect of the present
disclosure;

[0011] FIG. 4 is another graphical representation of the virtual
environment, depicting a simulation of the second virtual machine
footprint along a second virtual lane corresponding to a second proposed
route plan, according to another aspect of the present disclosure;

[0012]FIG. 5 is another graphical representation of the virtual
environment, depicting a simulation of a plurality of virtual machine
footprints along a first virtual lane of a third proposed route plan
according to an exemplary work cycle, with respect to another aspect of
the present disclosure;

[0013]FIG. 6 is another graphical representation of the virtual
environment, depicting a simulation of a plurality of virtual machine
footprints along first and second intersecting virtual lanes of a fourth
proposed route plan according to another exemplary work cycle, according
to another aspect of the present disclosure;

[0014] FIG. 7 is another graphical representation of the virtual
environment, depicting a simulation of a plurality of virtual machine
footprints along first and second intersecting virtual lanes of a fifth
proposed route plan, according to another exemplary work cycle, according
to another aspect of the present disclosure; and

[0015]FIG. 8 is an exemplary chart depicting evaluation designations
assigned to each of the plurality of potential route plans based on the
previously depicted simulations, according to another aspect of the
present disclosure.

DETAILED DESCRIPTION

[0016] Referring to FIG. 1, a control system 10 for a work site 12
includes a central control system 14 communicatively coupled with a first
autonomous machine 16 and a second autonomous machine 18 at the work site
12. According to a specific example, the work site 12 may be a mine
environment utilizing heavy equipment, such as excavators, backhoes,
front-end loaders, mining shovels, etc., to excavate and transport
materials across a terrain 20 from a mine site to a production facility.
Each of the autonomous machines 16 and 18 are equipped for land, or
ground, based travel and include a chassis 22 supporting a plurality of
ground engaging elements 24. As should be appreciated, the autonomous
machines 16 and 18 occupy actual footprints 26 and 28, respectively,
relative to the terrain 20. Although specific work site and machine
embodiments are described, it should be appreciated that the virtual
environment and method described herein are broadly applicable to a
variety of work sites including any combination of autonomous,
semi-autonomous, and manned machines.

[0017] Each of the autonomous machines 16 and 18 may include a machine
control system 30 supported on the chassis 22. For example, the machine
control system 30 of autonomous machine 16 may include an electronic
controller 32, a positioning unit 34, and a navigation unit 36. The
electronic controller 32 may be configured for drive-by-wire operation of
the autonomous machine 16 and, thus, may be in control communication with
various components of the machine 16 to control at least the speed and
direction of travel of the machine 16 according to an autonomous machine
movement profile 38. The autonomous machine movement profile 38, as will
be described below, may include at least a predetermined acceleration
rate, a predetermined deceleration rate, and a predetermined turning
radius for the machine 16. As should be appreciated, the electronic
controller 32 may also be in communication with various sensors and
devices in order to monitor and, thus, effectively control the operation
of the autonomous machine 16. Although a control strategy is described
with specific reference to machine 16, it should be appreciated that
autonomous machine 18 may be controlled in a similar manner.

[0018] The navigation unit 36 may receive, access, and/or store a route
plan that may be used to control operation of the autonomous machine 16.
For example, the route plan may include a map of the work site 12 that
includes positions of the equipment, materials, hazards, etc. located at
the work site. The route plan may also include an intended travel path
along a lane associated with a task for the machine 16. The navigation
unit 36 may be in communication with the positioning unit 34, which may
include one or more Global Positioning System (GPS) units receiving
information from satellites 40 to calculate machine position information.
The navigation unit 36 may use the machine position information to
ascertain where the autonomous machine 16 is currently located and where,
according to the route plan, the machine 16 must go. In particular, the
navigation unit 36 may receive an intended travel path for the machine 16
from the route plan and may communicate with the electronic controller 32
to maneuver the machine 16, such as by controlling propulsion, steering,
braking, and the like, according to the instructions set out for the
machine 16.

[0019] The electronic controller 32, the navigation unit 36, and the
positioning unit 34 may each be of standard design and may include a
processor, such as, for example, a central processing unit, a memory, and
an input/output circuit that facilitates communication internal and
external to the respective electronic device 32, 34, or 36. The processor
may control operation of the respective electronic controller 32,
navigation unit 36, or positioning unit 34 by executing operating
instructions, such as, for example, computer readable program code stored
in memory, wherein operations may be initiated internally or externally
to the respective electronic device 32, 34, or 36. A control scheme may
be utilized that monitors outputs of systems or devices, such as, for
example, sensors, actuators, or control units, via the input/output
circuit to control inputs to various other systems or devices.

[0020] The memory may comprise temporary storage areas, such as, for
example, cache, virtual memory, or random access memory, or permanent
storage areas, such as, for example, read-only memory, removable drives,
network/internet storage, hard drives, flash memory, memory sticks, or
any other known volatile or non-volatile data storage devices. Such
devices may be located internally or externally to the respective
electronic controller 32, navigation unit 36, or positioning unit 34. One
skilled in the art will appreciate that any computer based system or
device utilizing similar components for controlling the components of the
autonomous machine 16 or 18 is suitable for use with the present
disclosure.

[0021] As should be appreciated, each of the autonomous machines 16 and 18
may include other systems and/or components to effect autonomous control.
For example, the autonomous machines 16 and 18 may also be equipped with
inertial measurement devices, which tell the machine control systems 30
how the respective machine 16, 18 is moving. The machine control system
30 may also include additional obstacle detection and avoidance features,
including laser, vision, and radar sensors. All of these devices may be
used in known ways to maneuver the autonomous machines 16 and 18
according to instructions provided in the route plan.

[0022] The machine position information from each of the autonomous
machines 16 and 18 may be transmitted from the machines 16 and 18 to the
central control system 14. In particular, each machine 16, 18 may include
a wireless transceiver for communicating with the central control system
14 over a wireless network, such as via a wireless communication tower
42. A wireless transceiver 44 of the central control system 14 may
communicatively couple the wireless communication tower 42 with a network
46. As should be appreciated, the network 46 may include information
devices adapted to communicate over various wired or wireless media, such
as, for example, cables, phone lines, fiber optic lines, radio waves,
power lines, or the like. In addition, the network 46 may be private,
public, packet-switched, circuit-switched, local area, wide area,
Internet, intranet, IP, wireless, and/or any equivalents thereof.

[0023] The central control system 14 may also include a computing device,
such as a computer 48, having a display or graphical interface 50 and an
input device 52. The computer 48 may also include an electronic processor
54, such as a central processing unit, and a memory 56, and may be in
communication with a database 58 via the network 46. The components of
the computer 48 may be similar to the electronic controller 32, the
navigation unit 36, and the positioning unit 34 and, thus, will not be
described in further detail. The memory 56 and/or database 58 may include
a software program or algorithm 60, which may include computer readable
program code executable by the processor 54, to perform the functionality
described herein. The memory 56 and/or database 58 may also store one or
more route plans 62 for controlling the operation of autonomous machines
16 and 18 at the mine site 12. Further, the memory 56 and/or database 58
may store virtual movement profiles 64, which will be accessed and
utilized as described below.

[0024] Turning now to FIG. 2, a virtual environment 70 for sorting among a
plurality of potential route plans for operating the autonomous machine
16, 18 at the work site 12 will be described. The virtual environment 70
may be created at the central control system 14 or, more particularly, at
the computer 48, and may include a graphical depiction 72, which may be
displayed on display 50. The virtual environment 70 may be electronically
constructed by first creating a virtual model 74 of the actual terrain 20
of the work site 12. The virtual terrain model 74 may be created by use
of a computer aided design (CAD) program, such as AutoCAD, which is
provided by Autodesk, Inc. of San Rafael, Calif. The virtual terrain
model 74 may depict the topography and contours of the mine site 12 and
may be constructed using aerial maps, previous topographic maps, survey
reports, and the like.

[0025] Next, a first virtual lane 76 corresponding to a first proposed
route plan 78 may be created within the virtual environment 70. In
particular, the first virtual lane 76 may represent a potential or
proposed lane or road through the mine site 12 that may be incorporated
into a route plan. To evaluate lane suitability, the potential lane may
be modeled along the virtual terrain 74 as first virtual lane 76. The
first virtual lane 76 has a plurality of measurable lane constraints,
which are based on proposed lane constraints, including a width w1
defined by a left-hand boundary 80 and a right-hand boundary 82. The
first virtual lane 76 also has a plurality of curves, which may be
evaluated, for example, by measuring a radius of the curvature r1 at
point 84. The radius of curvature may be calculated using the equation:
{[1+(dy/dx) 2] 3/2}/|d 2y/dx 2|, where x and y are Cartesian coordinates
at the point 84. Although a specific example is provided, it should be
appreciated that the curvature of first virtual lane 76 may be calculated
using any known equation.

[0026] The first virtual lane 76 may also have an angle of inclination
a1 relative to the horizontal at any given point along the lane 76.
Although inclination angle is described, it should be appreciated that
the grade or slope of the first virtual lane 76 may be measured or
calculated in any number of ways to arrive at a representative value. The
measurable lane constraints may be stored in the memory 56 and/or
database 58 and may be provided for any or all points along a length of
the first virtual lane 76. Although specific examples are provided, it
should be appreciated that the first virtual lane 76 may have additional
and/or alternative measurable lane constraints that may be modeled in the
virtual environment 70.

[0027] A first virtual machine footprint 86, which may correspond to the
actual footprint 26 of autonomous machine 16, may also be created in the
virtual environment 70. In particular, the first virtual machine
footprint 86 may represent the two-dimensional, or three-dimensional,
space occupied by the autonomous machine 16 in the virtual environment
70, and may correspond to a coordinate system, in relation to the first
virtual lane 76. Further, the orientation, or angular shifting, of the
first virtual machine footprint 86 may also be represented in the virtual
environment 70. The first virtual machine footprint 86 may be initialized
at a desired position and orientation within the virtual environment 70,
which may correspond to a desired starting position for the machine 16 at
the mine site 12.

[0028] The first virtual machine footprint 86 has a first virtual movement
profile 88, which may correspond to the actual autonomous movement
profile 38 of the autonomous machine 16. In particular, the same logic
from the machine control system 30 described above may be used to control
movement of the first virtual machine footprint 86 in the virtual
environment 70. In particular, the first virtual movement profile 88 may
include at least a predetermined acceleration rate 90, a predetermined
deceleration rate 92, and a predetermined turning radius 94, which each
correspond to the respective value provided in the actual autonomous
movement profile 38 for the machine 16.

[0029] After the proposed lane or road has been modeled in the virtual
environment 70 as first virtual lane 76, and the first virtual machine
footprint 86 has been created and initialized relative to the first
virtual lane 76, the processor 54 moves the first virtual machine
footprint 86 from a starting position 96 along the first virtual lane 76
to an ending position 98 along the first virtual lane 76. In particular,
the processor 54 moves the first virtual machine footprint 86 along an
intended travel path 100, which may represent a centerline of the first
virtual lane 76, according to the first virtual movement profile 88. In
particular, the processor 54 is provided with a map (i.e., the virtual
terrain 74 and first virtual lane 76) and is instructed to move the first
virtual machine footprint 86 from the starting position 96 to the ending
position 98 along the lane 76 according to the first virtual movement
profile 88. As should be appreciated, by moving the first virtual machine
footprint 86 along the intended travel path 100 according to the first
virtual movement profile 88, movement of the autonomous machine 16 along
a proposed lane or road represented by the first virtual lane 76 may be
simulated.

[0030] While the first virtual machine footprint 86 is moved along the
first virtual lane 76, the first virtual machine footprint 86, along with
aspects of the first virtual movement profile 88, are compared to one or
more of the measurable lane constraints. For example, dimensions of the
first virtual machine footprint 86 may be compared to the width w1
of the first virtual lane 76 as the virtual machine footprint 86 is moved
along the intended travel path 100 according to the movement profile 90.
In particular, the first virtual machine footprint 86 may be compared to
the boundaries 80 and 82 to identify a breach of the boundaries 80 and 82
during the simulated movement. Such a simulation may predict whether the
autonomous machine 16 would breach real life boundaries of the proposed
lane, if the proposed lane were constructed at the mine site 12.

[0031] In addition, the turning radius 94 of the first virtual machine
footprint 86 may be compared to the curvature of the first virtual lane
76, as indicated by the radius of curvature r1, while the first
virtual machine footprint 86 is moved along the first virtual lane 76.
The movement capabilities of the first virtual machine footprint 86, as
defined by the first virtual movement profile 88, may also be compared to
the dynamic angles of inclination a1 of the first virtual lane 76 as
the first virtual machine footprint 86 is moved along the intended travel
path 100. As such, the simulation may predict whether the autonomous
machine 16 would be capable of navigating the curves and grades of the
proposed road while the machine 16 is operated autonomously.

[0032] These comparisons, along with comparisons of other measurable lane
constraints, may be used by the processor 54 to designate the first
proposed route plan 78 or, more specifically, the first virtual lane 76
as either viable or unacceptable. Although additional criteria may be
used, an "unacceptable" route plan or lane may be one that cannot be
successfully traversed by the autonomous machines 16, 18 given the
predetermined constraints, while a "viable" route plan or lane may be one
that is successfully traversed in the virtual environment 70. For
example, if the first virtual machine footprint 86 crosses one of the
boundaries 80 and 82 during the simulated movement, the first virtual
lane 76 may be deemed unacceptable. If, however, the first virtual
machine footprint 86 does not cross the boundaries 80 and 82, the first
virtual lane 76 may be deemed viable. Of course, it may be desirable to
determine whether or not a route plan is viable based on an evaluation of
any or all of the measurable lane constraints.

[0033] For exemplary purposes, the processor 54 may determine that the
first virtual machine footprint 86 successfully traverses the first
virtual lane 76, when moved according to the first virtual movement
profile 88 and compared to the provided constraints. However, if
different types of machines are to be operated along the proposed road,
it may be desirable to simulate movement of different machines (i.e.,
machines having different footprints and different machine movement
profiles) along the first virtual lane 76. For example, as shown in FIG.
3, a second virtual machine footprint 110 may be created which
corresponds to the actual footprint 28 of the autonomous machine 18 and
has a second virtual movement profile 112 that is different than the
first virtual movement profile 88. Specifically, the second virtual
movement profile 112 may correspond to an actual movement profile of the
autonomous machine 18 and may include at least a predetermined
acceleration rate 114, a predetermined deceleration rate 116, and a
predetermined turning radius 118.

[0034] After the second virtual machine footprint 110 is created and
initialized, the processor 54 may also be configured to move the second
virtual machine footprint 110 from the starting position 96 along the
first virtual lane 76 to the ending position 98 along the first virtual
lane 76. While the second virtual machine footprint 110 is moved along
the first virtual lane 76, the second virtual machine footprint 110,
along with aspects of the second virtual movement profile 112, are
compared to one or more of the measurable lane constraints of the first
virtual lane 76. For example, dimensions of the second virtual machine
footprint 110, which may be different than those of the first virtual
machine footprint 86, may be compared to the width w1 of the first
virtual lane 76 during the simulated movement. In addition, the turning
radius 118 of the second virtual machine footprint 110 may be compared to
the curvature of the first virtual lane 76, as indicated by the radius of
curvature r1. Further, the movement capabilities of the second
virtual machine footprint 110, as defined by the second virtual movement
profile 112, may also be compared to the dynamic angles of inclination
a1 of the first virtual lane 76 as the second virtual machine
footprint 110 is moved along the intended travel path 100.

[0035] These comparisons, along with the comparisons of the first virtual
machine footprint 86 relative to the measurable lane constraints, may be
used by the processor 54 to designate the first proposed route plan 78
or, more specifically, the first virtual lane 76 as either viable or
unacceptable. For exemplary purposes, the processor 54 may identify a
breach of the boundaries 80 and 82 during movement of the second virtual
machine footprint 110 along the first virtual lane 76, as shown at a
simulated position 120 of the second virtual machine footprint 110. As
such, although the first virtual machine footprint 86 successfully
traversed the first virtual lane 76, the first virtual lane 76 may be
deemed unacceptable because of the identified boundary breach with
respect to the second virtual machine footprint 110.

[0036] If the first proposed route plan 78 or first virtual land 76 is
deemed unacceptable, it may be desirable to evaluate an alternative route
plan or road in the virtual environment 70. Turning now to FIG. 4, the
virtual environment 70 may be used to evaluate a second proposed route
plan 130 having a virtual lane 132 that is different than the first
virtual lane 76. In particular, the virtual lane 132 may have different
measurable lane constraint values than those of the first virtual lane
76. For example, if it was determined that the autonomous machine 18 is
unable to navigate the curves of the first virtual lane 76 based on the
simulation, it may be desirable to propose or model a lane having smaller
curvature radii than the first virtual lane 76. As shown, the alternative
virtual lane 132 has a width w2 defined by a left-hand boundary 134
and a right-hand boundary 136. The virtual lane 132 also has a plurality
of curves, which may be evaluated, for example, by measuring a radius of
the curvature r2 at a point 138, and an angle of inclination a2
relative to the horizontal at any given point along the lane 132.

[0037] The processor 54 may move the second virtual machine footprint 110
from a starting position 140 along the virtual lane 132 to an ending
position 142 along the virtual lane 132. In particular, the processor 54
may be configured to move the second virtual machine footprint 110 along
an intended travel path 144, which may represent a centerline of the
virtual lane 132, according to the second virtual movement profile 112.
During the simulated movement, dimensions of the second virtual machine
footprint 110 may be compared to the width w2 of the virtual lane
132. In addition, the turning radius 118 of the second virtual machine
footprint 110 may be compared to the curvature of the virtual lane 132,
as indicated by the radius of curvature r2, and the movement
capabilities of the second virtual machine footprint 110 may be compared
to the dynamic angles of inclination a2 of the virtual lane 132. As
such, the simulation may predict whether the autonomous machine 18 would
be capable of navigating the proposed road while the machine 18 is
operated autonomously. If it is determined that the second virtual
machine footprint 110 successfully traverses the virtual lane 132, it may
be desirable to evaluate movement of different machines along the virtual
lane 132. If all of the machines that might operate along the proposed
route can successfully traverse the virtual lane 132, the second proposed
route plan 130 may be deemed viable.

[0038] The processor 54 may also be configured to measure and evaluate
additional parameters during the simulation. For example, turning now to
FIG. 5, a third proposed route plan 160 may be evaluated in the virtual
environment 70. In particular, the third proposed route plan 160 may
include a virtual lane 162 having a plurality of measurable lane
constraints that is modeled along the virtual terrain 74. The third
proposed route plan 160 may also include instructions for moving a
plurality of virtual machine footprints 164, which may correspond to a
fleet of autonomous vehicles, according to a predetermined work cycle.
For example, the work cycle may include the movement of material from one
location 166 to another location 168. It should be appreciated that the
precise locations 166 and 168 within the virtual environment 70 may
correspond to actual locations at the mine site 12.

[0039] The processor 54 may move the fleet of virtual machine footprints
164 along the virtual lane 162, which may be a two-lane road, according
to the respective virtual machine movement profile of each of the machine
footprints 164. In addition to comparing the fleet of machine footprints
164 and the respective virtual machine movement profiles to the
measurable lane constraints of the virtual lane 162, as described above,
the processor 54 may evaluate additional parameters, including a cycle
time 170 and a wait time 172.

[0040] For example, an exemplary work cycle for a fleet of autonomous
machines may include loading material at the first location 166, hauling
the material from the first location 166 to the second location 168,
unloading the material at the second location 168, and returning to the
first location 166. The processor 54 may be configured to simulate
movement of the virtual machine footprints 164 according to this work
cycle for a predetermined number of cycle times 174 or until another
measurable criteria are met. The cycle time 170 and wait time 172 may
both be initialized to zero and, when the simulation begins, may be
incremented as desired.

[0041] The cycle time 170 may be configured to measure elapsed time and,
thus, may provide a total time required for executing the defined work
cycle a predetermined number of times or until the task is completed. The
wait time 172 may keep track of the time that one or more of the virtual
autonomous machine footprints 164 is required to wait, or maintain a
stationary position, during the simulation. For example, a machine may be
required to wait if an upcoming destination is occupied or if there is a
delay during loading and/or unloading. High wait times 172 may indicate
decreased efficiency and/or productivity and may prompt reevaluation of
the proposed route plan 160. To aid in the evaluation, the wait time 172
and/or cycle time 170 may be compared to one or more acceptable time
values 176. Based on the comparison, the proposed route plan 160 may be
designated as either viable or unacceptable.

[0042] A fourth proposed route plan 190 may be evaluated in the virtual
environment 70, as described with reference to FIG. 6. In particular, the
fourth proposed route plan 190 may include a first virtual lane 192 and a
second virtual lane 194, both of which have a plurality of measurable
lane constraints. The first and second virtual lanes 192 and 194 may be
two-lane roads and may have at least one intersection 196, as shown. The
fourth proposed route plan 190 may also include instructions for moving a
plurality of virtual machine footprints 198-210 according to respective
virtual movement profiles and according to a predetermined work cycle.
For example, the work cycle may be similar to the work cycle described
above with reference to FIG. 5 and may include the movement of materials
at the mine site 12.

[0043] The processor 54 may be configured to simulate movement of the
virtual machine footprints 198-210 according to the work cycle for a
predetermined number of cycle times 212 or until other measurable
criteria are met. A cycle time 214 and a wait time 216 may both be
initialized to zero and, when the simulation begins, may be incremented
as described above, and either or both of the times 214 and 216 may be
compared to one or more acceptable time values 218. As with autonomous
control in the real environment, the virtual machine footprints 198-210
in the virtual environment 70 should be aware of the current positions of
other of the machine footprints 198-210 to avoid collision. As such, the
processor 54 may also be configured to modify movement of one of the
virtual machine footprints 198-210 based on a current virtual position of
another of the virtual machine footprints 198-210. Thus, as should be
appreciated, the wait time 216 and/or cycle time 214 may be affected by
traffic flow.

[0044] After a predetermined period of time, such as after the simulation
has run a predetermined number of cycle times 212, the cycle time 214
and/or the wait time 216 may increase, such as above the acceptable time
value 218, as shown in FIG. 7. In particular, the proposed route plan 190
may be evaluated based on operation for 32 cycles. As shown in FIG. 7,
the elapsed time for completing the 32 cycles was 10:23:11, which is
greater than the acceptable cycle time of 9:10:00. As such, the fourth
proposed route plan 190 may be deemed unacceptable and aspects of the
route plan 190 may be re-evaluated and revised. It should be appreciated
that an undesirable wait time 216 may also render the proposed route plan
190 unacceptable. Although determinations regarding the suitability of a
route plan may be made based on comparisons to measurable constraints, it
should be appreciated that some determinations may be made based on
visual inspection of the simulation. For example, as reflected in FIG. 7,
it may be apparent from visual observation that bunching is occurring
near the intersection 196.

[0045] As shown in FIG. 8, a chart 230 depicting evaluation designations
assigned to each of the plurality of potential route plans 78, 130, 160,
and 190 may be created and stored at the central control system 14. Row
232 reflects the determination that the proposed route plan 78 is
unacceptable at least because the second virtual machine footprint 110
was unable to successfully navigate the first virtual path 76 within the
given constraints. The second proposed route plan 130, however, was
deemed viable, as shown in row 234 of the chart 230. The third proposed
route plan 160 was deemed viable after evaluating measurable lane
constraints and additional criteria related to proposed work cycles, as
reflected in row 236. Finally, the fourth proposed route plan 190, as
shown in row 238, was determined to be unacceptable due to traffic flow
issues, as indicated by cycle and/or wait time evaluations and visual
observation.

[0046] When a plurality of proposed route plans, lanes, or roads are
evaluated using the virtual environment 70, it may be desirable to sort
or rank the modeled plans or lanes based on measurable results. Thus,
additional simulation data may be collected, stored, and used to
facilitate such evaluations. Regardless of the number of route plans or
roads that are evaluated using the virtual environment 70, it should be
appreciated that the modeling and simulation in the virtual world 70 may
save considerable time and money during the route planning process. As
should be appreciated, an actual lane or road may only be constructed at
the actual mine site 12 after it has been evaluated in the virtual world
70 and deemed suitable for autonomous machine traversal.

INDUSTRIAL APPLICABILITY

[0047] The present disclosure finds potential application in route
planning for a work site. Further, the present disclosure may be
specifically applicable to a virtual environment and method for
evaluating a proposed route plan for operating an autonomous machine at
the work site. Yet further, the disclosure may be applicable to sorting a
plurality of potential lanes for a route plan for an autonomous machine.
Such work sites may include mining environments utilizing autonomous and
manned heavy equipment, such as excavators, backhoes, front-end loaders,
mining shovels, etc., to excavate and transport materials from a mine
site to a production facility.

[0048] Referring generally to FIGS. 1-8, an exemplary control system 10
for an autonomous work site 12 includes a central control system 14
communicatively coupled with autonomous machines 16 and 18 at the work
site 12. The autonomous machines 16 and 18 may each include a control
system 30 supported on a chassis 22 and including an electronic
controller 32, a positioning unit 34, and a navigation unit 36. The
electronic controller 32 is configured for drive-by-wire operation of the
autonomous machine 16, 18 and, thus, is in control communication with
various components of the machine 16, 18, including the positioning unit
34 and the navigation unit 36, to control at least the speed and
direction of travel of the machine 16, 18. Generally, the navigation unit
36 may receive route plan information, such as from stored route plans
62, from the central control system 14 that is used to control operation
of the autonomous machine 16, 18.

[0049] Typically, the route plan information 62 will be validated to
ensure the autonomous machines 16 and 18 may successfully navigate the
designated lanes. In particular, a manned, autonomous, or semi-autonomous
machine may be operated along a constructed lane at the mine site 12 to
verify the suitability of the lane for autonomous operation prior to the
incorporation of the constructed lane into the route plan 62. Although
this real world validation is beneficial, actual machine operation at the
mine site 12 for testing or validation purposes is both time consuming
and costly, particularly if the constructed lane is found to be
unsuitable and must be modified or moved. The virtual environment 70 and
methods described herein provide an efficient and less costly alternative
to real world route plan validation.

[0050] In particular, and as described above, one or more proposed roads
may be modeled along a virtual terrain 74 corresponding to the mine site
12. The modeled or virtual lanes 76, 132, 162, 192, and 194 have a
plurality of measurable constraints, such as, for example, width w1
or w2, curvature radius r1 or r2, and/or inclination angle
a1 or a2, based on constraints of the one or more proposed
roads. Virtual machine footprints 86, 110, 164, and 198-210 corresponding
to real world autonomous machines 16 and 18 are created in the virtual
environment 70 and moved along the virtual lanes 76, 132, 162, 192, and
194 according to virtual machine movement profiles 88, 112, and 64 that
correspond to actual machine movement profiles, such as 38, of the
machines 16, 18. While the virtual machine footprints 86, 110, 164, and
198-210 are moved, the footprints 86, 110, 164, and 198-210 and virtual
movements are compared to the measurable lane constraints and additional
criteria to evaluate suitability of the virtual lanes 76, 132, 162, 192,
and 194. Acceptable or preferred lanes may then be constructed at the
mine site 12 and incorporated into route plans 62 for the autonomous
machines 16 and 18.

[0051] Since work sites, such as mine sites, are dynamic and require the
construction or modification of roads relatively frequently, the
disclosed virtual environment and method may result in a significant
reduction in time and costs for route planning purposes. In particular,
the virtual environment and method disclosed herein may be used to
validate proposed lanes and roads prior to their actual construction in
the real world and, thus, reduce the possibility that a constructed road
will need to be modified or moved based on unsuitability. In addition,
the virtual environment and method are particularly useful for route
planning for autonomous machines, since the control of the autonomous
machines may be more precisely replicated in the virtual environment.

[0052] It should be understood that the above description is intended for
illustrative purposes only, and is not intended to limit the scope of the
present disclosure in any way. Thus, those skilled in the art will
appreciate that other aspects of the disclosure can be obtained from a
study of the drawings, the disclosure and the appended claims.

Patent applications by Craig Lawrence Koehrsen, East Peoria, IL US

Patent applications by Eric Alan Moughler, Germantown Hills, IL US

Patent applications by Caterpillar Inc.

Patent applications in class SIMULATING NONELECTRICAL DEVICE OR SYSTEM

Patent applications in all subclasses SIMULATING NONELECTRICAL DEVICE OR SYSTEM